Method of making beryllium fluoride



" UNITED STATES, mew-[emce- METHOD, OF MAKIN BEBYLIJUM FLUOBIDE Charles B. warmer-e, New 1r ChcwmDetroit, Mich,

Company of America, Pittsburgh,

Frank D. Aluminum n, Pm, and asaignors to Pa; a corporation of Pennsyl No Dra wing. Original application April 24, 1943, Serial No. 484,477. Divided and this application February 20, 1945, Serial No. 578,942

1 Claim. (61.23-88) This invention relates to the production of beryllium fluoride whichis a compound usable as a source of metallic beryllium as well as for other purposes. One object of the invention is to provide simple and economical methods by which beryllium may be extracted in the form of a fluoride iromsiliceous beryllium ores such as, for example, the mineral beryl. Beryl is a berylliumaluminum silicate generally described by the tormuia BesAlz(Sisia). practical purposes, as being composed of the oxides of beryllium, aluminum and silicon. Theoretically it contains about 5 per cent by weight of beryllium, although, asmined, it often contains as little as.3.5 per cent of that metal. Another object of the invention is the provision of methods by which beryllium oxide, or materials or mixtures containing the same, may be treated to form beryllium fluoride.

by treatment which do not involve the use of chemical solutions.

The invention comprises a process in which the material which afiords a source of beryllium is mixed with aluminum fluoride and the mixture heated to cause reaction between the components thereof and the evolution therefrom of a vapor containing beryllium, which vapor may then be condensed and the condensate used or, if desirable or necessary, further treated to recover beryllium fluoride in substantially pure form. We have found that the temperatures necessary to promote the reaction in such a. mixture are low, particularly when reduced pressures are used, and

thus compatible with commercial operating con I ditions and available equipment. We have further found that the presence of magnesium fluoberyllium fluoride, all of which are articular described and explained in the IolIowingspeciflc description of the methods of this invention.

When beryl, or other siliceous ore oi beryll um,

45 producing a mass ham and aluminum and the product or reduction is the substanceto betreated. it is first desirable to eliminate therefrom all or a greater part 0! the silica prior to the treatment with aluminum fl u-; will be preferentially formed, when ore-aluminum fluoride mixtine on may not, within the sense or thiainvention,

5 ing of the mixture of It can be considered, for;

A further object is to provide methods by which these objects may be achieved num 30 ore or the reaction mixture, although this may. iii desired, be eflected; rather it means that the silica is either removed or converted in situ to silicon or to a silicon com readily react with aluminum fluoride in the heatalumi'num fluoride and source of beryllium or otherwise render ineffective the'iiuorine of .the aluminum fluoride The step or eliminating the silica from the ore may therefore consist of any one or several treatments which will either reduce the silica to metallic silicon or will change the silicate a compound which is stable. asregards aluminum fluoride, at the temperatures of the proposed reaction. While there are several or such treatments, we prefer 16 the following which have given good results and first groundto s finely divided form, is mixed with sufiicient carbon to-reduce its is then heated at high temperature, such as 1900 C. or higher, with the result that the silica is re- .duced to metallic silicon which then alloys with the iron to form term-silicon which is tapped oil, leaving a molten slag substantially tree of silica and composed of the oxides of beryllium and alumiheated at a temperature high enough to cause the silica to be reduced and permit the silicon to 8-1? loy with the iron-to form term-silicon, but not high enough to melt the oxides of beryllium and aluminum. For example, a temperature of about 1300" c. or higher may be used satisfactorily. The mo-silicon formed is not separated from the rest oi the charge.

(0) The beryl is mixed with sufllcient carbon to 40 reduce the silica accordins to the reaction Be3Ah(SiO:) c- |-18C 3heO+AhO:-i-6SiC+12co and the mixture heated to temperatures or about 1500 to 1800 C. to produce said reaction. thus,

' of the oxides of berylct indicated kalimetal fluoridetoiormwitlithesilicapresent the fluosillcate resin where R metal. This I reaction to iormsaldiflucsillcate.

beecnvenlentl! practiced as a mean the physical removalor 56 lium'fluorlde-producinu in which col which does not cury isused fluoride is also added as described below}; the

the beryl, but the silica rialferro-$ilicon in one carbide in in the otherwhich is not noticeably reactive is changed to a matecase, probably silicon in making the briquettes contains volatile mate rials, these should preferably be driven on by a prel heating at 'less than reaction tem: peratures.

than beryllium mixture. Consequently, it is desirable to furnish sufilcient aluminum fluoride in heated. If the heating takes, place at atmospheric pressures, the temperature should be maintained at at least 1000" 0., and for best results a temperature of at least 1200 C. is preferred. By conducting the reaction at reduced pressures'somewhat lower temperatures can'be employed without lowering the speed and efll- 'ciency of the'operatlon; however, even when aresidual Pressure 01' as we as 0.15 mm-. oi merthetemperature employed should be at least 700',

1000" C. If a doublefluoride of aluminum and alkali metal is another, and alkali metal fluosllicate' used as a source of aluminum fluo- 'ride, either for purposes oi convenience or, as 75 thoroughly in the proportions of ,72 part by with the principles or C. and, for best results, at least i u pointed out above, for the ing alkali metal fluoride to perature of at least 1100 C. should be used, and when the reaction is at reduced pressure a temincrease the efllcienoy oi the reaction, at least in the sense of greater ields per unit time. The exact' action of these materials is not entirely Set forth below are production or beryllium fluoride in thisinvention: Example I Finely ground beryl and carbon were mixed accordance specific examples of the k weight or beryl and as parts by weight flcient to reduce the silica,'and alsomixina mixture was heated at about 2000 C. and the resultant mainina' ride 27 'mm. or mercury and or carbon, pressure. The briquettes l600 c., beryl to silicon carbide. The briquettes and aluminum fluoride were ground togather to 100 mesh size or flner, the mix consistins or 140 beryl, and 60 parts by weight or aluminum fluomixture was then. placed in one end or a closed horizontal retort through pressure, whil beryllium fluoride, and 13 per cent aluminum fluoride. The beryllium fluoride represented 60 per cent of the beryllium present in the carbonreduced beryl.

Emmple H bymixina with iron. The I term-silicon separated from the re alas. This eiaa. which contained about 8'! per cent by weight or beryllium oxide, the balance being aluminum oxide, was then mixed with aluminum fluoride and magnesium fluoride in the following approximate pro- Aiter parts by weight or the carbon-reduced v which a flow heated at 1200 to convert the i the form or beryllium fluoride. about 83 per cent 0! shoe beini comprised ride and eslum fluoride,

Example I" v beryllium 01 aluminum fluo- Aluminum fluoride and beryllium oxide, ground thoroughly t of beryl:

mixed arts by weigh arts by weight or aluminum e was briquetted under briquettes were D closed. horizontal retort having a pump attached to the opposite end and were heated at 1000 C. for 1 hour, after which the heating was continued for 4 hours while the residual nae pressure-in the retort was maintained at 24 mm. of mercury by means or the vacuum p. The portion of the rurnace adjacent the end to which the vacuum pump was attached remained cool enough to condense the vapors produced item the briquet Upon being opened,

' limate composed of fluoride and 18 per cent ahnnin and the beryllium fluoride represented '10 per cent or the beryllium present in the original mix. This application is a division or our copendina application, Serial No. 484,417, flied April 24, 1948.

we claim: The method or recovering beryllium values in beryllium fluoride from siliceous which com rises 'iormins a mixfluoride and a sunlito at least mesh size, in the proportions of 45 p lium oxide and at tem erature densing the resultant-yawn v (gunmen? wnmonn. men! n. cnnw,

fluoride. the bad- 

